Evaluating Indoor Exposure Modeling Alternatives for LCA: A Case Study in the Vehicle Repair Industry

Abstract

We evaluated three exposure models with data obtained from measurements among workers who use "aerosol" solvent products in the vehicle repair industry and with field experiments using these products to simulate the same exposure conditions. The three exposure models were the: 1) homogeneously-mixed-one-box model, 2) multi-zone model, and 3) eddy-diffusion model. Temporally differentiated real-time breathing zone 3 volatile organic compound (VOC) concentration measurements, integrated far-field area samples, and simulated experiments were used in estimating parameters, such as emission rates, diffusivity, and near-field dimensions. We assessed differences in model input requirements and their efficacy for predictive modeling. The One-box model was not able to resemble the temporal profile of exposure concentrations, but it performed well concerning time-weighted exposure over extended time periods. However, this model required an adjustment for spatial concentration gradients. Multi-zone models and diffusion-models may solve this problem. However, we found that the reliable use of both these models requires extensive field data to appropriately define pivotal parameters such as diffusivity or near-field dimensions. We conclude that it is difficult to apply these models for predicting VOC exposures in the workplace. However, for comparative exposure scenarios in life-cycle assessment they may be useful.

Investigation of A Potted Plant (Hedera helix) with Photo-Regulation to Remove Volatile Formaldehyde for Improving Indoor Air Quality

“…Workplaces in health care facilities, research institutes, and mortuaries may present the high exposure risks due to the use of chemicals (Demou et al, 2009). However, many studies have investigated the removal kinetics of VOCs with a short-term exposure in a controlled space.…”

“…However, specific pathogens or causes cannot be identified in most cases. Therefore, a well-defined experimental platform needs to characterize the major components, distributions, boundaries, exchangeable rate, and loading between the system and surroundings (Freijer and Bloemen, 2000;Yang and Zhang, 2008;Demou et al, 2009;Kim et al, 2010). The indoor air quality is significantly influenced by infiltration into the building mainly through the ventilation system and to a lesser extent, through windows or cracks .…”

Integrating Indoor environmental quality metrics in a dynamic life cycle assessment framework for buildings

“…Recent research has begun to incorporate IEQ into LCA, with a particular focus on integrating the IAQ and human health toxicity categories [5][6][7]. The intakes of specific contaminants are estimated based on emissions data and building-level variables, such as ventilation rates and indoor emissions rates.…”

An Approach to Integrating Occupational Safety and Health into Life Cycle Assessment: Development and Application of Work Environment Characterization Factors

“…, ; Demou et al. ). In the compartment model approach, a characterization factor represents an intake fraction for indoor exposure to chemicals and a human effect factor (Hellweg et al.…”

“…The compartment model approach is based on exposure assessment modeling techniques that consider the amount of chemical released in an exposure area (a compartment) of a certain volume, the emission rate into the area, the ventilation rate, the inhalation rate of the people in the area, and the number of people exposed (Hellweg et al 2005Demou et al 2009). In the compartment model approach, a characterization factor represents an intake fraction for indoor exposure to chemicals and a human effect factor ).…”